Number of treatment cycles influences development of cytotoxic T cells in metastatic breast cancer patients - a phase I/II study

Antitumor activity of human γδ T cells transducted with CD8 and with T-cell receptors of tumor-specific cytotoxic T lymphocytes

The difficulty in the induction and preparation of a large number of autologous tumor-specific cytotoxic T lymphocytes (CTL) from individual patients is one of major problems in their application to adoptive immunotherapy. The present study tried to establish the useful antitumor effectors by using γδ T cells through tumor-specific TCRαβ genes transduction, and evaluated the efficacy of their adoptive transfer in a non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice model. The TCRαβ gene was cloned from the HLA-B15-restricted CTL clone specific of the Kita-Kyushu Lung Cancer antigen-1 (KK-LC-1). The cloned TCRαβ as well as the CD8 gene were transduced into γδ T cells induced from peripheral blood lymphocytes (PBL). Cytotoxic T lymphocyte activity was examined using a standard 4 h (51) Cr release assay. Mice with a xenotransplanted tumor were treated with an injection of effector cells. Successful transduction of TCRαβ was confirmed by the staining of KK-LC-1-specific tetramers. The γδ T cells transduced with TCRαβ and CD8 showed CTL activity against the KK-LC-1-positive lung cancer cell line in a HLA B15-restricted manner. Adoptive transfer of the effector cells in a mice model resulted in marked growth suppression of KK-LC-1- and HLA-B15-positive xenotransplanted tumors. Co-transducing TCRαβ and CD8 into γδ T cells yielded the same antigen-specific activity as an original CTL in vitro and in vivo. The TCRαβ gene transduction into γδ T cells is a promising strategy for developing new adoptive immunotherapy.